The invention relates to a fire closure shutter.
Especially in the ventilation ducts in ships there is a need for fire closure shutters the purpose of which is to separate, in the event of fire, the area under fire from the other spaces of the ship. The cross-sectional area of this kind of air duct can be about two square meters and the fire closure shutter must form a barrier able to close the whole of this area. For the acceptance of a fire closure shutter a fire test is arranged in which at one side of the closed shutter a temperature corresponding to that of a fire prevails for one hour. Severe thermal stress caused during the fire test generally causes distortion of the elements of the shutter creating non-acceptable gaps in the barrier created by the elements of the shutter.